package com.atguigu.gulimall.product.service.impl;

import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;
import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    // 因为ServiceImpl中已经提供了baseMapper, 其实就是CategoryDao, 不用再注入了
    // @Autowired
    // private CategoryDao categoryDao;

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        // 1. 查出所有分类
        List<CategoryEntity> entities = baseMapper.selectList(null);

        // 2. 组装成父子结构
        // 2.1 找到一级分类(父分类id为0)
        List<CategoryEntity> level1Menus = entities.stream()
                // 获得一级菜单
                .filter(categoryEntity -> categoryEntity.getParentCid() == 0)
                .map(categoryEntity -> {
                    categoryEntity.setChildren(getChildrens(categoryEntity, entities));
                    return categoryEntity;
                })
                // 根据sort升序排序
                .sorted((menu1, menu2) -> menu1.getSort() - menu2.getSort())
                .collect(Collectors.toList());

        return level1Menus;
    }

    @Override
    public void removeMenuByIds(List<Long> longs) {
        // TODO 删除前检查要删除的菜单, 是否被别的地方引用
        baseMapper.deleteBatchIds(longs);
    }

    /**
     * 递归获取所有父菜单的子菜单
     *
     * @param root 当前菜单
     * @param all  所有菜单
     * @return
     */
    public List<CategoryEntity> getChildrens(CategoryEntity root, List<CategoryEntity> all) {
        List<CategoryEntity> children = all.stream()
                .filter(categoryEntity -> categoryEntity.getParentCid().equals(root.getCatId()))
                .map(categoryEntity -> {
                    // 找到子菜单
                    categoryEntity.setChildren(getChildrens(categoryEntity, all));
                    return categoryEntity;
                })
                // 菜单的排序, sort有可能为空, 需处理
                .sorted((menu1, menu2) ->
                        (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 :
                                menu2.getSort()))
                .collect(Collectors.toList());

        return children;
    }
}